hashtable

I have a list of objects, each containing an Id, Code and Description. I need to convert this list into a Hashtable, using Description as the key and Id as the value. This is so the Hashtable can then be serialised to JSON. Is there a way to convert from List<Object> to Hashtable without writing a loop to go through each item in the list? Let's assume that your List contains objects of type Foo (with an int Id and a string Description). You can use Linq to turn that list into a Dictionary like this: var dict = myList.Cast<Foo>().ToDictionary(o => o.Description, o => o.Id); If you have access

I am trying to use JAXB to serialize a HashTable<String, String> to XML. I am very new to Java (came from C#), so I am kinda perplexed by this task. I have seen the following code: public static <T> String ObjectToXml(T object, Class<T> classType) throws JAXBException { JAXBContext jaxbContext = JAXBContext.newInstance(classType); StringWriter writerTo = new StringWriter(); Marshaller marshaller = jaxbContext.createMarshaller(); marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true); marshaller.marshal(object, writerTo); //create xml string from the input object return writerTo

I'm writing a Haxe C# target, and I've been studying performance differences for Haxe's std library so we can provide the best performance possible through its cross platform code. One very good example is for the hash table code. I was a little reluctant about using .NET's Dictionary, as it seems bulky (structs for key/value pairs can take up a huge amount of memory because of memory alignment issues, besides from unnecessary information held by it), and since on the std library there is no such thing as an object hash, I really thought I could squeeze a little performance by not having to

Is there any way to implement hash tables efficiently in a purely functional language? It seems like any change to the hash table would require creating a copy of the original hash table. I must be missing something. Hash tables are pretty darn important data structures, and a programming language would be limited without them. Is there any way to implement hash tables efficiently in a purely functional language? Hash tables are a concrete implementation of the abstract "dictionary" or "associative array" data structure. So I think you really want to ask about the efficiency of purely

Eclipse source menu has a "generate hashCode / equals method" which generates functions like the one below. String name; @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((name == null) ? 0 : name.hashCode()); return result; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; CompanyRole other = (CompanyRole) obj; if (name == null) { if (other.name != null) return false; } else if (!name.equals(other.name)) return false; return true; } If I

I have a Hashtable<string,string> , in my program I want to record the values of the Hashtable to process later. My question is: can we write object Hastable to a file? If so, how can we later load that file? Yes, using binary serialization ( ObjectOutputStream ): FileOutputStream fos = new FileOutputStream("t.tmp"); ObjectOutputStream oos = new ObjectOutputStream(fos); oos.writeObject(yourHashTable); oos.close(); Then you can read it using ObjectInputStream The objects that you put inside the Hashtable (or better - HashMap ) have to implement Serializable If you want to store the Hashtable in